Various crystalline titanosilicate catalysts are known and some of them are known as being effective catalysts for the production of epoxy compounds by epoxidation of olefins, the productions of phenol compounds or polyhydroxyphenyl compounds by hydroxylation reactions, of benzene or phenol compounds, respectively, or the like.
In addition, the present invention relates to a crystalline titanosilicate catalyst having an MWW structure. The MWW structure is a framework type code name specified by International Zeolite Association (IZA). A crystalline metallosilicate (zeolite) having an MWW structure is known as the name of MCM-22. Therefore a crystalline titanosilicate catalyst having an MWW structure, which contains titanium (hereinafter referred to as Ti) within the framework, is known as the name of Ti-MWW, or Ti-MCM-22, or the like.
Additionally, this crystalline titanosilicate having an MWW structure is also known to be a useful material as a catalyst.
Generally, enhancing the activity of a catalyst can lead to reduction of the amount of the catalyst and thus reduction of the catalyst cost, and also to lower the cost of reaction vessel by reducing its size, and therefore further enhancement of the catalyst activity of the Ti-MWW catalyst is also desired.
As a method of highly activating the Ti-MWW catalyst, a method of increasing the Ti content is known (e.g., Chemical Communication 897, (2001)), but it is known that a high Ti content with the Ti to Si (silicon) ratio being 1/40 or more deteriorates the crystallinity of the Ti-MWW catalyst (e.g., Journal of Physical Chemistry B, 105, 2897, (2001)). In general, with a crystalline titanosilicate catalyst, poorer crystallinity is accompanied by lesser catalyst performance in some cases. As such, a novel method of highly enhancing the activity of a catalyst except for increase of Ti content is needed.